Protective sheet for cassette holding magnetic recording tape

Abstract

A protective sheet for a cassette holding a magnetic recording tape comprises a transparent base which is coated with a hardened surface layer formed by bonding hard fine particles with a binder.

I claim: 
     
       1. A protective sheet for a cassette holding a magnetic recording tape which comprises a transparent base which is coated with a hardened surface layer formed by bonded hard fine particles made of a mixture of Al 2  O 3 , TiO 2  and SiO 2  with a binder wherein a ratio of said hard fine particles to said binder is in a range of about 1/2 to about 1/10 by weight. 
     
     
       2. The protective sheet according to claim 1 wherein said transparent base is a synthetic resin film and said binder for forming said hardened surface layer is a synthetic resin which is similar in properties to said base film. 
     
     
       3. The protective sheet according to claim 1 wherein said hardened surface layer is substantially uniformly coated on said transparent base. 
     
     
       4. The protective sheet according to claim 1 wherein said hardened surface layer is coated on said transparent base in a lattice pattern. 
     
     
       5. The protective sheet according to claim 1 wherein said hardened surface layer is prepared by coating on said transparent base in random pattern. 
     
     
       6. A protective sheet of claim 1 wherein proportions by weight of Al 2  O 3  :TiO 2  :SiO 2  in said mixture is about 2 to 30:0 to 30:98 to 50.